Why would it have few friends?
Are you joking? I already explained this in the post. In order to fully withdraw its forces from around the globe in such a short timespan, the US would be breaking many of its treaty obligations; which would be enough to piss countries off by itself, but especially so given that the world is now less stable than it was just ten years ago and most of the traditional US allies are faced with nearby powers that are experiencing alarming upsurges in belligerent militarism.
Europe is already largely fed up with the US over many things; if the US withdrew its forces from around the world, there'd be very little reason for us to not start openly treating the US as a hostile power.
Japan is facing territorial disputes with China, and have spent decades banking on the US to protect them. They will be profoundly upset if the US just up and left. This response would be even more amplified for South Korea.
That leaves what, Australia & New Zealand? They're far enough away from any potential conflicts that they probably wouldn't be too bothered if the US did this. Then again, they also wouldn't have any particular incentive to be friendly towards an isolationist US either; they'd be better off cozying up to China or a resurgent EU that tries to fill the global police role gap.
Canada would probably find itself forced to not cut the US off like the rest of the world would; but their foreign politics seem more in line with Europe than the US so who can say.